County Donegal has an amateur weather forecaster whose fame has grown as his predictions come true. This year he claims Ireland is in for a bitterly cold winter, complete with heavy snowfall before Christmas.

Unlike the experts at Met Eireann (Ireland's national weather forecasters), who can’t seem to agree on the forecast for this week, Donegal postman Michael Gallagher has no doubt about what's ahead. It's easy when you know how to study the clues being dropped by plants and animals.

'I have never seen as many berries on the trees in the mountains and the birds are singing loudly in recent days,' Gallagher told The Sun. 'The abundance of berries is a sure sign that temperatures are going to plunge in the winter.'

Gallagher's track record is not in doubt; he correctly predicted a white Christmas three years ago.

But Irish climatologist Professor John Sweeney doesn't believe anyone can predict Irish weather more than ten days in advance. Said Sweeney: 'We have no confidence that we can go more than ten days ahead and anyone who says we can is being quite imaginative.

'Most national meteorological services have given up seasonal forecasting. A few summers back the UK met office had an attempt at a seasonal weather forecast and they forecast a barbecue summer but they got it badly wrong. Met Eireann wisely never got into that.'

Sweeney cautioned: 'Some people will base forecasts on phenomena such as berries on trees. There may be some element of truth in it, but in general the natural world responds to what has gone before it, instead of what’s coming.'

Meanwhile, across the pond in Britain, Jim Dale from British Weather Services agrees with postman Gallagher and says he believes the early cold spell could be a signal of more to come.

'We do put out monthly and 90-day forecasts in British Weather Services for both Ireland and the UK,' he told the Kildare Nationalist. 'We do see a colder than average winter, we do see that. Now that doesn't necessarily follow that we're going to see the depths of 2010 again.'